We know that vertical angles are congruent and corresponding angles are congruent if they are formed by parallel lines.
Step-by-step explanation:
Therefore, We can use this information to prove alternate interior angles are also congruent if they are formed by parallel lines since the lines are parallel, then < 1 and < 5 are congruent, < 2 and < 6 are vertical angles We also know that all vertical angles are congruent, so that means < 1 congruent to < 5 because they are corresponding angles, and < 2 congruent to < 6 because they are vertical angles, that means < 1 must be congruent too.
